Am I Crazy to Try This?

[clifftt]

In talking with a transmission shop, the likely cause that my car will not move is that I damaged the front trans pump while trying to install the new motor. They guess it will run me about $400 to replace the pump and other gaskets and seals. My question is this: I've never torn down an automatic transmission. It's a 904 push-button. How hard would it be to go thru this thing? It seemed to shift well before I pulled and rebuilt the engine, the fluid coming out was pretty clean and red.

My credentials: I built this 273, have built other engines: a 440, an MGB, Opel, but never opened a tranny before.

Should I tackle this or pay someone else to do it?

 

[65barracudadude]

Well, I've heard that once you get the basic understanding of the internals of an automatic, then things are fairly self explanitory. But, I've never done anything but change out the filter in one myself. So, I really dont know what you should do. I guess you could just try it out and if things do not work out then take it in. It cannot hurt to try. Right?

 

[camd64]

I would say go for it. there are a few guys on here that are more than qualified to talk you through it if something does come up. I too have rebuilt a few motors and ended up going through an allison auto in a dump truck and it wasn't that bad. just a bunch of tolerences really. I ended up buying my 904 already done but that was because I got a screaming deal and didn't have a core to work with anyway.

 

[1qwikScamp]

Well, I've heard that once you get the basic understanding of the internals of an automatic, then things are fairly self explanitory. But, I've never done anything but change out the filter in one myself. So, I really dont know what you should do. I guess you could just try it out and if things do not work out then take it in. It cannot hurt to try. Right?

agreed

 

[needsaresto]

I guess it depends on several things. You need a VERY clean workspace. The tranny must be spotless of course when put back together.
You need a couple days to do this. Compressed air is essential for cleaning and testing servo's. A manual is essential as well. A good heavy duty snap ring plier is essential as well. I have a KD and it works fine. A lift is great! But I have put transmissions in and out using nothing but my arms and a floor jack. I would also pull the crossmember with the tranny and replace the mount while Im at it. It seems to be a bit easier this way rather than trying to wrestle the tranny up over the X member. A pair of long bolts that will mate your trans to the motor are great helpers. They give you the room to slide the tranny back much further while getting you tq converter back in and help tremendously with alignment to the motor. I also block the rear of the motor up tightly before pulling the trans,so it does not drop. This will prevent a huge fight trying to get the trans and motor to mate back up.

They are not hard as everything is a subassembly. I take one assembly out,rebuild it,clean it and set it aside. Then the next etc. Then it's just a matter of checking tolerances and torqeuing correctly.
There are some bigass heavy duty springs inside that WILL fly acroos the shop given the chance.
AND IT MUST BE SPOTTLESS!!!! Dirt and crap seem to really affect the performance and life. Wash everything in solvent ,then spray down with brake cleaner and wipe down with lint free towels or rags. Do not use carb cleaner as it will leave a residue. I would take the housing and pressure wash the majo crap off,then go nuts with yor favorite cleaning method.

DO NOT attemt this if you cant get the thing clean.

 

[fishy68]

Torqueflites are very simple transmissions. When I was 17 in high school shop class I pulled one out and rebuilt it and it worked fine. Until that point I had never seen the insides of a transmission. I suggest getting a manual and reading through it first. ATSG markets a rebuild manual that mimics the factory service manual with a few extra helpful tips. Very good investment. Here's a link to the place that sells them,

http://www.bulkpart.com/Merchant2/merchant.mvc?Screen=CTGY&Store_Code=2&Category_Code=A904manuals

Oh yeah needsaresto is right about needing a clean place to work and a way to properly clean the parts. The valves in the valve body are super sensitive to dirt/lint/particles, etc. I take my bare transmission cases to the local NAPA to have them pressure cleaned. only costs $15 and saves a couple hrs. work and $3 for degreaser and $5 at the car wash so you can't beat it.

 

[clifftt]

Thanks for all your replies. I appreciate the advice.

 

[blufie]

I doubt the pump costs that much and the sealing rings and gaskets are cheap from the local tranny parts/gear shop... the pump is easy to get off, little harder to get back on right the first time but if it was just the pump you could replace it. Usually not just the pump unfortunatley and you may be "in for a penny" then in for a full rebuild at the shop. I have built several 727's in my garage and even though I have tried to be clean they are never spotless. I have never had to re-build any of the ones I did but most never saw more than a few thousand miles a year behind 300-400 hp engines.

If you are mechanical in nature and have the time, get a book and have at it. Otherwise let the shop handle it.

If you have 3 matching 'C' clamps of the proper size, you can even handle the drum springs easily. Also, most front pumps have two holes on opposing sides that are threaded for larger bolts so after you remove the ones around the side, find the threaded ones and use long threaded bolts to evenly work the pump out (hold the center shaft before you yank the pump or you will remove the front drum with it... this is not a huge issue as you will remove it anyway. Good luck!